[Induction of IgE-Fc receptor (Fc epsilon RII/CD23) expression on stimulated monocytes by mite allergen in patients with asthma].

The low affinity IgE-Fc receptors (Fc epsilon RII/CD23) show an important role in atopic disorders such as bronchial asthma. Since monocytes/macrophages could be contributed to allergic inflammation through IgE stimulation, I examined Fc epsilon RII/CD23 expression on peripheral blood monocytes in patients with bronchial asthma. The expression of Fc epsilon RII/CD23 on monocytes was higher in asthmatic patients than in normal control subjects. Furthermore when peripheral blood monocytes in patients with mite-allergic asthma (RAST score > or = 3) were additionally stimulated by mite allergen, the expression of Fc epsilon RII/CD23 increased and remained after culture with mite allergen. In order to investigate the mechanisms of the induction of Fc epsilon RII/CD23, I examined the effects of the supernatants on Fc epsilon RII/CD23 expression on monocytes, using the monocytic cell line U937. Our findings were that the supernatants of mononuclear cells from mite allergic patients cultured with mite-allergen, as well as IL-4, induced Fc epsilon RII/CD23 expression on U937 cells, while anti IL-4 antibody almost but not completely inhibited the induction of Fc epsilon RII/CD23 expression on U937 cells by the supernatants, suggesting a possibility that Fc epsilon RII/CD23 expression on monocytes might be mainly regulated by IL-4 in combination with various cytokines.